appreciate it. >>> a special moment to show you between nelson mandela and his great grandson. it's believed to be the last photo taken of the iconic leader. take a look at this picture. it was just taken in may, a month before mandela was hospitalized. the boy's father said that he took the picture believing that it might be the last time to capture them together. this being released as world leaders prepare to attend memorials in mandela's honor. chris cuomo is in johannesburg. >> reporter: here in johannesburg, the long good-bye is in full effect. in front of the his house, the celebration is taking on the character of the man himself. there's a complexity, a lot of dancing and singing. but at the same time there's a sense of purpose that reflects what's going on inside the family's home where they're grieving for the loss of a loved one who meant so much to them and so much to the entire world. tuesday we'll see the largest gathering of world leaders in africa's history. the massive soccer stadium was big enough for the world cup. but the 90,000 seats will hold just a fract